ARM: bcm2835_defconfig: Enable wifi driver for RPi Zero W

This enables the wifi driver for Raspberry Pi Zero W. We need
to build this as a module otherwise the drivers tries to load the
firmware before the root partition is mounted.
Signed-off-by: NStefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NEric Anholt <eric@anholt.net>

arch/arm/configs/bcm2835_defconfig

@@ -63,6 +63,7 @@ CONFIG_SCSI_SCAN_ASYNC=y
 CONFIG_NETDEVICES=y
 CONFIG_USB_USBNET=y
 CONFIG_USB_NET_SMSC95XX=y
+CONFIG_BRCMFMAC=m
 CONFIG_ZD1211RW=y
 CONFIG_INPUT_EVDEV=y
 # CONFIG_LEGACY_PTYS is not set